Turn Arduino on/off with 433mhz wireless relay


I know how to program but I am a beginner at working with electrical circuits. I recently ordered several components: FT5330M-35KG servo motor, 433mhz wireless remote relay, Arduino starter kit (wires, resistors & diodes).
So I want to be able to remotely turn on / off the Arduino itself. Searching for info in various forums and google, I created the following electrical wiring diagram. the question is whether it will work or some changes are needed?

You MUST wire the relay in series with the 7.5 volt supply and the Arduino power. Really hard to see what you have with your diagram.

Looks like you intend to have the relay powered all the time the Arduino is turned off. Seems strange. How have you programmed to remote control receiver?

Looks like you are not supplying any power to the Arduino.

When the relay is off (NC connected to COM), Vin is connected to GND.
When the relay is on (NC not connected to COM), Vin is connected to nothing.

Just to be clear... the relay does not supply power... it is simply a switch.

Normally you would connect your power source to the COM (Common) terminal.
The thing you want to power would connect to NO (normally open) terminal.

When the relay is activated COM will be connected to NO.

NC (normally closed) is the opposite of NO... you don't need that in your case.

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Well, that circuit will not.

I gather that you expect to save battery power using the remote control. Well, as well as the problem with correctly wiring the relay in series with the 7.5 V power from the batteries to "Vin" on the UNO, there is the more significant matter of the batteries on the remote control going flat reasonably quickly.

If we can credit the quoted 5 mA standby current, alkaline AA batteries at a quoted 2 Ah capacity would last 400 hours (16 days) on standby and 22 hours of (single) relay actuation.

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At the moment, I'm not worried about saving battery power, because I can access and disconnect batteries at any time (when not in use)). The idea here is that when I turn on the Arduino with the remote control, the setup () function executes the code that starts the servo motor, when it is done, I can turn off the Arduino.

Did I get it right?

The way you have it wired, your remote turns the arduio OFF only when the relay is powered up by your remote. The waste is the remote battery pulling in the relay all the time the Arduino is OFF.

NC means "normally closed"

Not quite...

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